Editorial: Cognitive enhancement: are we barking up the wrong tree?

Abstract

There are surprisingly few studies directly comparing the effects of nutraceutical and pharmaceuticals. However, a recent comparison of effects sizes (Cohen's d) from studies on modafinil and ginseng (and the long term benefits of Bacopa) was conducted [16]. In non sleep deprived individuals modafinil was associated with effect sizes ranging from d = 0.083 to d = 0.774. The latter was for accuracy of Visual Spatial Memory. For Ginseng there was larger variation in the effect sizes across mood and cognitive domains, ranging from d = -.340 (from a high dose of Ginseng) to d = 1.396. The latter related to reversal of self-rated mental fatigue during intense cognitive processing. In the context of cognitive processing the largest effect size (d = 0.860) was for simple reaction time. Thus it appears that herbal extracts may be at least as promising as pharmaceuticals as cognitive enhancers. Perhaps this is not so surprising when one considers that most pharmaceutical approaches to cognitive enhancement rely on the "magic bullet" approach to brain function. That is, they tend to target one neurotransmitter (or neurotransmitter family). It does seem unlikely that a phenomenon as complex as human cognitive function will benefit greatly from such an approach. Herbal extracts on the other hand, may contain multiple active components. These may exert multiple subtle effects which individually either have positive or negative effects on behaviour, but together may affect multiple neuronal, metabolic and hormonal systems which underpin behavioural processes. This polypharmacological approach may offer more promise in the context of cognitive enhancement.